KABUL, Afghanistan — The top contenders for Afghanistan's 2014 presidential elections all survived a preliminary disqualification round on Tuesday that eliminated 16 minor candidates for not meeting requirements, officials said.

Independent Elections Commission chief Ahmad Yousuf Nuristani said the disqualified candidates have 20 days to raise any objections to the commission. He added that 10 of the 26 candidates who registered by the Oct. 6 deadline made the cut.

Most of the eliminated candidates were barred because of improper documents and other violations, including dual nationalities and lack of university degrees, but the favorites all easily qualified for the vote.

Candidates had to declare tickets that included two vice presidents, and have at least 100,000 signatures that included ones from all 34 of Afghanistan's provinces.

"There are different reasons (for the disqualifications). Some of them had problems with documents, education levels, the number of registration signatures," Nuristani said. "They now have 20 days to criticize and complain."

All the candidates have tried to shape tickets that draw support from across an ethnically fractious political scene marked by patronage and alliances among the elite, including warlords and tribal elders who can marshal votes from their communities. The population of 31 million is roughly 42 percent Pashtun, 27 percent Tajik, 9 percent Hazara, and 9 percent Uzbek along with other, smaller factions. The Taliban are predominantly Pashtun.

The April 5 vote could determine the future course of Afghanistan and the level of foreign involvement here after 12 years of war.

President Hamid Karzai is not entitled to run for a third consecutive term in elections, but is expected to back at least one of the candidates — his former foreign minister Zalmai Rassoul, despite the fact that his businessman brother Qayyum Karzai is also running for president. Both men are Pashtun.

Other top contenders who remain in the running include former foreign minister Abdullah Abdullah, who was the runner up to President Hamid Karzai in the 2009 elections and dropped out just ahead of a runoff vote following allegations of massive fraud in the first round.

Another is Ashraf Ghani, a Pashtun former finance minister who oversaw the transition of security from foreign forces to the Afghan army and police. Ghani ran and lost in the 2009 elections.

Two former Afghan warlords who are sharing a ticket, one for president, the other for vice president, also qualified. They are Abdul Rab Rasoul Sayyaf, an influential Pashtun lawmaker and religious scholar, who is running for president along with former energy and water minister Ismail Khan, a Tajik.